package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.ScrollResult;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import com.sun.org.apache.regexp.internal.RE;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;
    @Resource
    private IBlogService blogService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;

    /**
     * 保存博客笔记
     * 并将笔记推送到所有粉丝的收件箱
     * @param blog
     * @return
     */
    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean isSuccess = blogService.save(blog);
        if (!isSuccess){
            return Result.fail("新增笔记失败");
        }
        //  查询笔记作者所有的粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //  推送笔记给所有粉丝
        for (Follow follow : follows){
            //获取粉丝id
            Long userId = follow.getUserId();
            String key = FEED_KEY + userId;
            // 推送
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(), System.currentTimeMillis());
        }
        // 返回id
        return Result.ok(blog.getId());
    }

    /**
     * 查询热门博客
     * @param current
     * @return
     */
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            //查询用户
            queryBlogUser(blog);
            //查询bolg是否被点赞
            isBlogLiked(blog);
        });
        return Result.ok(records);
    }
    /**
     * 查询博客详情
     * @param id
     * @return
     */
    @Override
    public Result queryBlogById(Long id) {
        // 查询博客
        Blog blog = getById(id);
        if (blog == null){
            return Result.fail("博客不存在");
        }
        //查询博客用户
        queryBlogUser(blog);
        //查询bolg是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    // 查询用户信息 封装
    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
    //封装 判断是否点赞 并返回boolean
    private void isBlogLiked(Blog blog) {
        UserDTO user = UserHolder.getUser();
        if (user == null){
            // 用户未登录，无需查询是否点赞
            return;
        }
        //获取当前用户id
        Long userId = UserHolder.getUser().getId();
        //判断当前用户是否点赞
        String key = BLOG_LIKED_KEY + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //设置blog的isLike属性  ture 已经点赞
        blog.setIsLike(score != null);
    }

    /**
     * 查询博客点赞 Top5
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        // 查询top5的点赞用户
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()){
            // 没有点赞数据
            return Result.ok(Collections.emptyList());
        }
        // 解析出用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        // 3.根据用户id查询用户 WHERE id IN ( 5 , 1 ) ORDER BY FIELD(id, 5, 1)
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        // 返回
        return Result.ok(userDTOS);
    }

    /**
     * 点赞
     * @return
     */
    @Override
    public Result likeBlog(Long id) {
        //获取当前用户id
        Long userId = UserHolder.getUser().getId();
        //判断当前用户是否点赞
        String key = BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if (score == null ){
            //未点赞
            //数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            if (isSuccess){
                //保存用户到redis的set集合
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else {
            //已点赞，点赞-1，修改数据库
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            //删除redis
            if (isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    /**
     * 好友关注-滚动分页查询
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        // 获取当前用户
        Long userId = UserHolder.getUser().getId();
        String key = FEED_KEY + userId;
        // 查询收件箱
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        // 非空判断
        if (typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        // 2.解析数据：blogId，minTime（时间戳），offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0; // 最小时间戳
        int os = 1; //偏移量
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            // 获取id
            String blogId = typedTuple.getValue();
            //将获取的id转换为Long类型，存入集合中
            ids.add(Long.valueOf(blogId));
            // 获取分数（时间戳）
            long time = typedTuple.getScore().longValue();
            // 如果时间戳相同，则偏移量+1  时间戳不同，重置偏移量 重新计数
            if (time == minTime){
                os++;
            }else {
                minTime = time;
            }
        }
        // 3.根据id查询blog
        //将ids集合转换为字符串 （以，分割）
        String idStr = StrUtil.join(",", ids);
        //根据id集合，查询博客信息，由于listByid 查询到的顺序不对，所以需要手动重新排序
        List<Blog> blogs = query()
                .in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        // 4.遍历查询 博客用户 以及 是否点赞
        for (Blog blog : blogs) {
            //查询博客用户
            queryBlogUser(blog);
            //查询bolg是否被点赞
            isBlogLiked(blog);
        }
        //5.封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);

        return Result.ok(r);
    }
}
